NOTE: I have updated this 2015 post in order to make it appear closer to the other mason bee information
When Mason bees are laying eggs in their tubes it is essential that they have an easily available source of wet soil for building the individual chambers in which the pollen and nectar are deposited and the eggs will be deposited . Separating each egg chamber is a mud wall and capping the tube at the entrance will be a mud plug. I have dug a trench a few metres from the nest boxes a metre long and about 20 cm deep in which I periodically soak with water. Along the walls of the trench I have poked small tunnels since I have observed that the mason bees prefer to go into horizontal holes to pick up the mud.
